In wiper blades, the mounting rails or carrying rails should ensure that the wiper blade contact pressure proceeding from the wiper arm is distributed as uniformly as possible at the window pane over the entire wiping field to be wiped by the wiper blade. Due to a corresponding curvature of the carrying rails when not loaded, that is, when the wiper blade does not contact the window pane, the ends of the wiper blade which rest entirely upon the window pane when the wiper blade is operating are loaded toward the window pane by the carrying rails which are tensioned in operation, even when the radii of curvature of spherically curved vehicle window panes change in every position of the wiper blade. The curvature of the wiper blade must accordingly be somewhat greater than the greatest curvature measured in the wiping field at the window pane to be wiped. Thus, the carrying rails replace the costly carrying clip construction having two spring rails arranged in the wiping strip that was used in conventional wiper blades (DE-OS 15 05 357).
The invention is based on a wiper blade according to the preamble of claim 1. In a known wiper blade of this type (DE 19 62 71 15.0 A1), the holder which is produced from sheet metal is furnished with bending tabs which are provided for forming claws and which are bent inward after placing the holder on the upper strip surfaces of the carrying rails, so that their ends grip their respective carrying rail. When the wiping strip is worn out, the entire wiper blade must be replaced even if the carrying rails and the holder are still intact. As concerns the operating safety of the wiper blade, this means that the bending tabs may not be bent back and then bent inward again after exchanging the used wiping strip.